Standard chemotherapy followed by allogeneic or autologous transplantation: The role of allogeneic transplantation in the AATT study.
Authors: Norbert Schmitz, Bettina Altmann, Birte Friedrichs, Krimo Bouabdallah, Guillaume Cartron, Maike Nickelsen, Gerald Wulf, Mathieu Leclerc, Alban Vilatte, Pascal Turlure, Roch Houot, Laurence De Leval, Philippe Gaulard, German Ott, Gandhi Laurent Damaj, Peter Reimer, Georg Lenz, Lorenz H. Trumper, Marita Ziepert, Olivier Tournilhac
Journal: Journal of Clinical Oncology (2022)

7534 Background: Prognosis of relapsed and refractory T-cell lymphoma patients (pts) is devastating. Early results of the AATT study (Autologous or Allogeneic Transplantation in T-cell lymphoma, Schmitz et al. ASCO 2019; NCT00984412) showed that standard chemotherapy followed by allogeneic transplantation (alloSCT) compared to autoSCT did not improve outcome of poor-risk patients. We wanted to investigate the long-term clinical course of AATT patients (pts) focusing on pts receiving alloSCT off study. Methods: AATT was a randomized trial comparing alloSCT with autoSCT in younger pts (18-60 yrs) with newly diagnosed PTCL who achieved stable disease or better after 4 courses of CHOEP and 1 course of DHAP. Pts were to receive BEAM/autoSCT or myeloablative conditioning/alloSCT from matched related or unrelated donors for consolidation. Local investigators gave updated detailed reports on all further therapy until last follow up or death in order to report long-term EFS and OS focusing on patients receiving alloSCT off study and after failing autoSCT. Results: 103 pts (median age 50 years) randomized to autoSCT (n = 54) or alloSCT (n = 49) formed the full analysis set (FAS), 67 pts (65%) actually received autoSCT (n = 41) or alloSCT (n = 26) (per protocol set, PPS). Median observation time for EFS (OS) was 80 (84) months in the FAS and PPS population. At 7 years EFS and OS were 36% [95%CI: 27% - 46%] and 58% [48-68] for all 103 pts; EFS and OS for patients randomized to autoSCT vs. alloSCT were 34% [22-47] vs. 38% [25-52] and 61% [47-74] vs. 55% [41-69]. For patients actually transplanted 7-year-EFS and -OS were 50% [34-66] vs. 61% [42-80] and 72% [58-86] vs. 61% [42-80]. None of these survival rates differed significantly. TRM was 0/41 (0%) after autoSCT and 8/26 (31%) after alloSCT. Relapse rates were 15/36 (42%) vs. 1/21 (5%) for patients auto- or allografted. Overall, 26/ 50 pts received alloSCT off study because of early relapse/ progression before transplantation or after failing autoSCT. 7-year-OS for these pts is 62% (43-80). Ten of 15 pts relapsing after autoSCT received alloSCT as next therapy. Eight of these pts remain alive 39 – 94 mos after transplantation 5-year-OS of 24 pts who did not receive alloSCT was 17% (2-32). Conclusions: Seven-year OS-rates for the FAS- and the PPS cohort are remarkably high (58% and 68%) reflecting the high rate of long-term survivors after alloSCT also in pts with early relapse and after autoSCT. Pts not undergoing alloSCT had a dismal outcome. For T-cell lymphoma pts with early progression/ relapse after first-line therapy or failing autoSCT alloSCT offers cure in a significant portion of pts and should therefore be the preferred option for all transplant-eligible pts. Clinical trial information: NCT00984412.